[dart2js] Use exactOrEmpty in RecordTypeMask.toFlatTypeMask When a record shape is uninstantiated in the closed world, RecordTypeMask.toFlatTypeMask falls back to the record arity class (e.g. _Record3). If no record literals are instantiated anywhere in the program, the arity class itself is also uninstantiated and has no strict subclasses. Using TypeMask.exactOrEmpty / TypeMask.nonNullExactOrEmpty ensures that an uninstantiated record arity class normalizes to an empty mask instead of triggering an assertion failure in TypeMask.assertIsNormalized. Also preserve special values (null, lateSentinel) in RecordTypeMask.createRecordWithPowerset when any field type is empty. Fixes https://github.com/dart-lang/sdk/issues/64100 TAG=agy CONV=bca542cb-694d-48a1-baac-322aa1508f0c Change-Id: Icd22328a35481d2af7e179a5e98c59d5163d05a6 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/549040 Reviewed-by: Nate Biggs <natebiggs@google.com> Commit-Queue: Stephen Adams <sra@google.com>
Dart is:
Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.
Portable: Compile to ARM, x64, or RISC-V machine code for mobile, desktop, and backend. Compile to JavaScript or WebAssembly for the web.
Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.
Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:
Dart Native: For programs targeting devices (mobile, desktop, server, and more), Dart Native includes both a Dart VM with JIT (just-in-time) compilation and an AOT (ahead-of-time) compiler for producing machine code.
Dart Web: For programs targeting the web, Dart Web includes both a development time compiler (dartdevc) and a production time compiler (dart2js).
Dart is free and open source.
See LICENSE and PATENT_GRANT.
Visit dart.dev to learn more about the language, tools, and to find codelabs.
Browse pub.dev for more packages and libraries contributed by the community and the Dart team.
Our API reference documentation is published at api.dart.dev, based on the stable release. (We also publish docs from our beta and dev channels, as well as from the primary development branch).
If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.
There are more documents in our repo at docs.
The easiest way to contribute to Dart is to file issues.
You can also contribute patches, as described in Contributing.
Future plans for Dart are included in the combined Dart and Flutter roadmap on the Flutter wiki.